Bolanical zyxwvutsrqponm Journal ofthe Linnean SocieQ zyxwvutsr (1992), 109: zyxwvuts 21 1-222. With 5 figures zyxwv Structure of the vascular cambium of varying age and its derivative tissues in the stem of Ficus rumphii Blume SAGHEER AJMAL Department zyxwvuts of Botany, Aligarh Muslim University, Aligarh 202 002, India AND MUHAMMAD IQBAL Department of Botany, Hamdard University, Hamdard Nagar, New Delhi 110 062, India Received zyxwvutsrqp May 1990, accepted for publication March 1991 AJMAL, S. & IQBAL, M., 1992. Structure of the vascular cambium of varying age and its derivative tissues in the stem of Ficrs rrrmpliii Blume. The cambial cells of Ficus rumphii and their derivatives vary in size and number with the age of the tree. The fusiform initials, vessel elements, sieve-tube members, xylem fibres and phloem fibres are relatively short in the terminal part of the stem axis, consistently longer down the stem reaching a maximum, and short again in the main trunk. The width of the respective cells shows a similar variation. The ray cell initials increase both in number and size, and form rays ofvarying dimensions. Uniseriate and biseriate cambial rays are abundant, while multiseriate rays are especially sparse in the young shoot. The proportion of uni- and biseriate rays falls in the lower part of the stem whereas that of multiseriate rays increases. Likewise, short cambial rays are abundant in young branches but their frequency decreases in the trunk region, leading to a rise of the tall ray population. The rays in the phloem and xylem regions reflect a similar variation pattern with certain fluctuations. The overall proportion of the rays increases in the older part of the axis, reaching a maximum tangential area in the trunk. The transectional area of vessel elements remains more or less constant down to the base after an initial increase in the terminal region, while the sieve-tube proportion tends to be constant in the basal region after a consistent gain from the tree top basewards. ADDITIONAL KEY WORDS:-Anatomy - cambium derivatives - Moraceae - ontogeny CONTENTS Introduction . . . . . . . . . . . . . . . . . . . 212 Material and methods . . . . . . . . . . . . . . . . 212 Observations . . . . . . . . . . . . . . . . . . . 2 zyx 13 Discussion . . . . . . . . . . . . . . . . . . . 219 References . . . . . . . . . . . . . . . . . . . 22 1 21 I 0024-4074/92/060211+ 12 $03.00/0 zyxwvut 0 1992 The Linnean Society of London